Photonic bandgap fibers: optical properties and device applications

Recently emerged photonic bandgap fibers with their extraordinary optical properties offer many interesting device applications. We present the status of our work on the use of this kind of a fiber in sensing and wavelength referencing both in the 1300 and 1500 nm wavelength regions. The photonic bandgap fibers are spliced to standard single-mode fibers at input end for easy coupling and filled with gas through the other end placed in a vacuum chamber. The technique is applied to measure absorption lines of strongly absorbing gases such as acetylene and hydrogen cyanide by employing tunable lasers and LEDs as light sources. The measurement of weakly absorbing gases such as methane and ammonia is also explored. To realize a permanent wavelength reference sealing of a photonic bandgap fiber using index-matching UV-curable adhesive is demonstrated.